Embedded Files
Original Air Duct and Redesign Boundary Conditions
This is the original air duct provided to us by our sponsor. The new duct design needed to have an optimized "flattened" shape that fits within the design boundaries colored in yellow, red, and green. The duct was 3D printed using resin plastic material into five different pieces where each piece was individually printed. There were also additional boundaries along the length of the duct such that it can be only modified in between the highlighted yellow lines.
The original air duct has an inner diameter (ID) of 1.32 in, an outer diameter (OD) of 1.42 in, and thickness (t) of 0.10 in.
Original Duct
Original Duct with Boundary Conditions
Original Duct Attached to Testbed Apparatus
Longitudinal Boundary Conditions
Final Elliptical Duct Design and Setup
Our final design consisted of an elliptical duct that fits within the boundary condition envelope and matched the original air duct characteristics. Its hydraulic diameter (to be explained soon) was modified and led to a semi-major axis value (A) of 1.75 in and a semi-minor axis value (B) of 0.41 in.
The final product was 3D printed via polylactic acid (PLA) plastic material.
Dimensions and CAD Renderings
Semi-major axis value (A) of 1.75 in and a semi-minor axis value of 0.41 in
Design Envelope dimensions:
Length = 3.5 in
Width = 1.12 in
Solidworks CAD Rendering of Elliptical Duct
Semi-major and Semi-minor Values Imposed onto Solidworks CAD Rendering
Elliptical Duct Within Design Envelope Boundary Conditions
Testbed Apparatus and Elliptical Duct
To test the original duct and the duct designs, the testbed composed of an Arduino, two test stands and differntial pressure transducers, an inlet/outlet adapter and the air duct.
The Arduino was used to implement code that measures the pressure using the pressure transducers at the inlet and outlet and feeds it to the computer for us to collect and analyze.
The test stands are adjustable and have their own adjustable clamps to move to a desired position.
The pressure transducers measure the pressure at the inlet and outlet.
Each adapter is connected to the pressure transducer and held by test stand clamps. The inlet is elongated and has an orifice made for air hose insertion, which is controlled by a pressure regulator connected to the air source in the ceiling.
The air pressure was used to its highest setting and connected to the air hose. We manipulated the pressure regulator for the desired pressures during experimentation.
Performance Analysis
Sponsor Equations and Basic Data
Before experimentation and in the computational fluid dynamics (CFD) analyses our sponsor provided us an example of flow parameter graph that should resemble ours.
We were also informed of critical equations to use for our plots: specifically for pressure ratio and flow parameter equation.
We also calculated the change in pressure loss, modified the hydraulic diameter (the parameter of the duct that can change flow) and analyzed the head loss to plot our data.
Experimental vs. Theoretical Data Analyses
Fig. 1 Original Duct
Fig. 2 Oval Duct (Final Design)
Fig. 3 Original Duct vs. Oval Duct
To ensure that the newly designed duct is able to capture similar characteristics as the original duct, we ran simulations and tests for both the original and oval ducts.
We analyzed the behavior of the original duct (Fig. 1) and the oval duct (Fig. 2) between Ansys Computation Fluid Dynamics (CFD) simulations and data that was collected from physically testing the ducts with our test setup as shown above.
This was done to ensure that the expected characteristics of the duct are seen within the real world and vice versa as they both should mimic one another.
Once that is achieved, we can then compare experimental results between the original and oval duct (Fig. 3) with confidence that the data is reliable.
As a result of CFD simulations and physical testing, the oval duct resulted in having the most similar behavior in relation to the original duct.
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